\documentclass[11pt,openright]{book}
\usepackage{array}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\renewcommand{\arraystretch}{1.2}
\usepackage{booktabs}
\usepackage{tabularx}
\usepackage{caption}
\usepackage{threeparttable}

\begin{document}



\def\onepc{$^{\ast\ast}$} \def\fivepc{$^{\ast}$}
\def\zeropc{$^{\ast\ast\ast}$}
\begin{table}
\centering
\scriptsize
\caption*{Likert Treatment vs. Likert+/QVSR (pooled) \label{bal1}}

\input{bal1.tex}


\begin{tablenotes}
		\item \fivepc $p$\textless.05, \onepc $p$\textless.01 \zeropc $p$\textless.001.
		\item \textit{Exp\_minW}: $=1$ if would benefit from min wage increase. \textit{Miss\_minW}: $=1$ if did not answer min wage items. \textit{Paid\_leave\_exp}: proximity to childbirth score (see Fig.5 notes). \textit{Gun\_exp}: see Table \ref{covariates}. \textit{Immi\_exp}: score capturing how many relatives are immigrants. \textit{MissV\_BA}: $=1$ if missing value on religion questions.
\end{tablenotes}
\end{table}


\end{document}